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ARS Home » Pacific West Area » Logan, Utah » Poisonous Plant Research » Research » Publications at this Location » Publication #345433
Title: Identification of indole diterpenes in Ipomoea asarifolia and Ipomoea muelleri, plants tremorgenic to livestock

Author
item Lee, Stephen
item Gardner, Dale
item Cook, Daniel

Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/2/2017
Publication Date: 6/2/2017
Citation: Lee, S.T., Gardner, D.R., Cook, D. 2017. Identification of indole diterpenes in Ipomoea asarifolia and Ipomoea muelleri, plants tremorgenic to livestock. Journal of Agricultural and Food Chemistry. 65:5266-5277. https://doi.org/10.1021/acs.jafc.7b01834.

Interpretive Summary: Ipomoea asarifolia has been associated with a tremorgenic syndrome in livestock in Brazil and was recently reported to contain tremorgenic indole diterpenes. Ipomoea muelleri has been reported to cause a similar tremorgenic syndrome in livestock in Australia. Ipomoea asarifolia and I. muelleri were investigated by liquid chromatography – mass spectroscopy for indole diterpene composition. The mass spectrometric data provided valuable information for indole diterpene characterization. The previous report of indole diterpenes in I. asarifolia was confirmed and expanded; and the presence of indole diterpenes in I. muelleri is reported for the first time. Two new indole diterpenes were isolated and their structures determined. Two other indole diterpenes in I. asarifolia were demonstrated for the first time. This is the first detailed mass spectrometric analysis of indole diterpenes and possible isomers in I. asarifolia and I. muelleri.

Technical Abstract: Ipomoea asarifolia has been associated with a tremorgenic syndrome in livestock in Brazil and was recently reported to contain tremorgenic indole diterpenes. Ipomoea muelleri has been reported to cause a similar tremorgenic syndrome in livestock in Australia. Ipomoea asarifolia and I. muelleri were investigated by HPLC-HRMS and HPLC-MS/MS for indole diterpene composition. The high resolution mass spectrometric data in combination with MS/MS fragmentation mass spectral data provided valuable information for indole diterpene characterization. The previous report of indole diterpenes in I. asarifolia was confirmed and expanded; and the presence of indole diterpenes in I. muelleri is reported for the first time. Two new indole diterpenes were isolated and their structures determined by 1D and 2D NMR spectroscopy and given the names 11-hydroxy-12,13-epoxyterpendole K and 6,7-dehydroterpendole A. The presence of terpendole K and terpendole E in I. asarifolia is unequivocally demonstrated for the first time. This is the first detailed MS analysis of known indole diterpenes and possible isomers in I. asarifolia and I. muelleri.